Chlorofluorocarbon (CFC) based chemicals have been widely used in industry in a variety of different applications including as refrigerants, aerosol propellants, blowing agents and solvents, among others. However, certain CFCs are suspected of depleting the Earth's ozone layer. Accordingly, more environmentally friendly substitutes have been introduced as replacements for CFCs. For example, 1,1,1,3,3-pentafluoropropane (HFC-245fa) is recognized as having favorable physical properties for certain industrial applications, such as foam blowing agents and solvents, and therefore is considered to be a good substitute for the CFCs previously used for these applications. Unfortunately, the use of certain hydrofluorocarbons, including HFC-245fa, in industrial applications is now believed to contribute to the global warming. Accordingly, more environmentally friendly substitutes for hydrofluorocarbons are now being sought.
The compound 1-chloro-3,3,3-trifluoropropene, also known as HCFO-1233zd or simply 1233zd, is a candidate for replacing HFC-245fa in some applications, including uses as blowing agents and solvents. 1233zd has a Z-isomer and an E-isomer. Due to differences in the physical properties between these two isomers, pure 1233zd(E), pure 1233zd(Z), or certain mixtures of the two isomers may be suitable for particular applications as refrigerants, propellants, blowing agents, solvents, or for other uses.
It is known that 1-chloro-3,3,3-trifluoropropene can be prepared through the fluorination of 1,1,1,3,3-pentachloropropane (HCC-240fa) in a liquid phase reactor. The uncatalyzed HCC-240fa fluorination using anhydrous HF is slow due to their low solubility and limited contact surface area between HCC-240fa and HF.
Also known are methods to improve the reaction rate and/or to elevate the conversion of HCC-240fa to 1233zd. These include an increase in the agitation speed and/or increase the reaction temperature. However, the increase in agitation speed can increase the contact surface area between two phases only to a certain degree. Thus, the reaction rate or the conversion is limited by the increase in the agitation speed. While it is true that the rate of a reaction is increased with increasing temperature, by-products are accompanied by elevating the solution temperature. Hence, there is a need for means by which the reaction rate can be improved without these detrimental impacts.